Anticalculus oral composition

ABSTRACT

An oral dentifrice composition such as a toothpaste, dental gel, toothpowder, dental tablet or lozenge containing as anticalculus agent about 4.3% to about 7% of alkali metal pyrophosphates comprising at least 4.3% of tetrapotassium pyrophosphate alone or admixed with up to 2.7% of tetrasodium pyrophosphate, and as inhibitors against enzymatic hydrolysis of such agent in saliva, a fluoride and preferably up to about 3% of a synthetic anionic polymeric polycarboxylate, and use of such composition in a program of oral hygiene and/or for inhibiting dental calculus.

This is a division of application Ser. No. 07/312,532 filed 3/20/86, nowU.S. Pat. No. 4,806,877, which was a continuation in part of applicationSer. No. 06/775,851 filed 9/13/85, now U.S. Pat. No. 4,627,977.

This invention relates to oral compositions containing an anticalculusagent.

Calculus is a hard, mineralized formation which forms on the teeth.Regular brushing aids in preventing a rapid build-up of these deposits,but even regular brushing is not sufficient to remove all of thecalculus deposits which adhere to the teeth. Calculus is formed on theteeth when crystals of calcium phosphates begin to be deposited in thepellicle and extracellular matrix of the dental plaque and becomesufficiently closely packed together for the aggregates to becomeresistant to deformation. There is no complete agreement on the route bywhich calcium and orthophosphate ultimately become the crystallinematerial called hydroxyapatite (HAP). It is generally agreed, however,that at higher saturations, that is, above the critical saturationlimit, the precursor to crystalline HAP is an amorphous ormicrocrystalline calcium phosphate. "Amorphous calcium phosphate"although related to hydroxyapatite differs from it in atomic structure,particle morphology, and stoichiometry. The X-ray diffraction pattern ofamorphous calcium phosphate shows broad peaks typical of amorphousmaterials, which lack the long-range atomic order characteristic of allcrystalline materials, including HAP. It is apparent therefore thatagents which effectively interfere with crystalline growth of HAP willbe effective as anticalculus agents. A suggested mechanism by which theanticalculus agents of this invention inhibit calculus formationprobably involves an increase of the activation energy barrier thusinhibiting the transformation of precursor amorphous calcium phosphateto HAP.

Studies have shown that there is a good correlation between the abilityof a compound to prevent HAP crystalline growth in vitro and its abilityto prevent calcification in vivo, provided of course that such compoundis stable in plaque, saliva and their components.

The prior art indicates that soluble pyrophosphate may be utilized toreduce calculus formation. For example, U.S. Pat. No. 4,515,772 issuedMay 7, 1985 to Parran et al. refers to several prior art referencesdisclosing oral compositions containing soluble pyrophosphate salts,including an article by Draus et al., Arch. Oral. Biol., 15, pp 893-896,(1970), which discloses the in vitro effectiveness of such salts againstcalculus. The article refers to possible inhibition of pyrophosphate bypyrophosphatase enzyme.

It is known that saliva contains acid phosphatase, alkaline phosphataseand pyrophosphatase enzymes. It is considered that any one of the threeenzymes may adversely affect pyrophosphates as an inhibitor of HAPformation and calculus. It is accordingly apparent that an anticalculuspyrophosphate dentifrice composition, should inhibit, reduce or nullifythe destructive activity of all three salivary enzymes

The compositions of the aforementioned Parran et al patent are limitedto a pH of 6.0 to 10.0 and comprise a fluoride and soluble dialkalimetal pyrophosphates alone or admixed with tetraalkali metalpyrophosphates, but no more than 4.0% K₄ P₂ O₇ (tetrapotassiumpyrophosphate) any disclosure or even mention of effectiveness of thepatented fluoride-pyrophosphate composition in vivo or saliva.

Said parent application Ser. No. 775,851 is concerned with oralcompositions containing as anticalculus agent one or a mixture of linearmolecularly dehydrated polyphosphate salts, including dialkali metal andtetraalkali metal pyrophosphates and as combination inhibitor againstenzymatic hydrolysis of said agent in saliva, a fluoride ion source anda synthetic anionic linear polymeric polycarboxylate. As stated therein,compounds providing a source of fluoride ion have been profuselydisclosed in the prior art as anticaries agent but not for inhibitingsalivary hydrolysis of linear polyphosphate salts employed asanticalculus agents. For example, in an article by G. W. Rapp et al inJ. Dent. Res. 39, 372-376 (1960) entitled "Pyrophosphate: A Factor inTooth Erosion", the erosive effects of relatively large amounts ofpyrophosphate accumulating in saliva and salivary debris in contact withtooth substance in producing eroded lesions on enamel, exposed dentinand cementum was studied. In these studies, fluoride from NaF wasemployed to inhibit hydrolysis of pyrophosphate by pyrophosphataseenzyme and thus permit accumulation of the pyrophosphate to determineits tooth erosion effects.

It is an object of this invention to provide an improved dentifricecomposition containing one or a mixture of pyrophosphate salts asessential anticalculus (antitartar) agent.

Another object of this invention is to provide such a compositioncontaining one or more inhibitors against enzymatic hydrolysis of saidagent in saliva.

Still another object of this invention is to provide such a compositioneffective over a relatively wide pH range and/or with improved cosmeticproperties.

A further object of this invention is to provide such a compositionwhich does not significantly erode tooth surfaces and which also exertssubstantial and acceptable anti-caries effects.

Yet a further object of this invention is the provision of an improvedmethod for inhibiting the formation of calculus. Other objects andadvantages will appear as the description proceeds. Earlier in thedevelopment of this invention, it was found that dentifrice compositionscontaining only tetrasodium pyrophosphate as anticalculus agent weregritty, and that the solid gritty particles were composed of undissolvedNa₄ P₂ O₇.

The present invention is at least in part based on our determinations ordiscoveries that fluoride ion inhibits hydrolysis of pyrophosphate byacid phosphatase and pyrophosphatase enzymes, that the synthetic anionicpolymeric polycarboxylate salts referred to in said parent applicationSer. No. 775,851 inhibit hydrolysis of pyrophosphate by alkalinephosphatase, and that the occurrence of gritty particles in the oralcompositions can be avoided by employing a predominant portion of thepyrophosphate in the form of the tetrapotassium salt.

In accordance with certain of its aspects, this invention relates to adentifrice composition in the form of a toothpaste, dental gel,toothpowder, dental tablet or lozenge containing an orally acceptablevehicle and, in approximate weight proportions,

A. 4.3% to 7% of alkali metal pyrophosphates as essential anticalculusagent, comprising at least 4.3% of tetrapotassium pyrophosphate, aloneor admixed with up to 2.7% of tetrasodium pyrophosphate, and asinhibitors against enzymatic hydrolysis of said agent in saliva,

B, an amount of a fluoride ion source sufficient to supply 25 ppm. to5,000 ppm. of fluoride ions, and

C. 0% to 3% of a synthetic anionic polymeric polycarboxylate having amolecular weight of about 1,000 to about 1,000,000.

Synthetic anionic polymeric polycarboxylates and their complexes withvarious cationic germicides, zinc and magnesium have been previouslydisclosed as anticalculus agents per se in, for example U.S. Pat. No.3,429,963 to Shedlovsky and instant assignee, U.S. Pat. No. 4,152,420 toGaffar and instant assignee, U.S. Pat. No. 3,956,480 to Dichter et al.and instant assignee, U.S. Pat. No. 4,138,477 to Gaffar and instantassignee, and U.S. Pat. No. 4,183,914 to Gaffar et al. None of thesepatents however nor any other known prior art, discloses use of suchpolycarboxylates alone for inhibiting salivary hydrolysis ofpyrophosphate anticalculus agents, much less in combination with acompound providing a source of fluoride ion. It is to be understood thatthe synthetic anionic polymeric polycarboxylates per se disclosed inthese patents are operative in the compositions and methods of thisinvention and such disclosures are to that extent incorporated herein byreference thereto.

The synthetic anionic polymeric polycarboxylates optionally butpreferably employed herein are, as indicated above, well known, beingemployed in the form of their free acids or partially or preferablyfully neutralized water soluble alkali metal (e.g. potassium andpreferably sodium) or ammonium salts. Preferred are 1:4 to 4:1copolymers of maleic anhydride or acid with another polymerizableethylenically unsaturated monomer, preferably methyl vinyl ether(methoxyethylene) having a molecular weight (M.W.) of about 30,000 toabout 1,000,000. These copolymers are available for example as Gantrez(AN 139 (M.W. 500,000), A.N. 119 (M.W. 250,000) and preferably S-97Pharmaceutical Grade (M.W. 70,000), of GAF Corporation. The term"synthetic" is intended to exclude known thickening or gelling agentscomprising carboxymethyl-cellulose and other derivatives of celluloseand natural gums. Also excluded are the zinc, magnesium and similarmetal complexes of these polymeric polycarboxylates.

Other operative polymeric polycarboxylates include those disclosed inU.S. Pat. No. 3,956,480 referred to above, such as the 1:1 copolymers ofmaleic anhydride with ethyl acrylate, hydroxyethyl methacrylate,N-vinyl-2-pyrollidone, or ethylene, the latter being available forexample as Monsanto EMA No. 1103, M.W. 10,000, and EMA Grade 61, and 1:1copolymers of acrylic acid with methyl or hydroxyethyl methacrylate,methyl or ethyl acrylate, isobutyl vinyl ether or N-vinyl-2-pyrrolidone.

Additional operative polymeric polycarboxylates disclosed in abovereferred to U.S. Pat. Nos. 4,138,477 and 4,183,914, include copolymersof maleic anhydride with styrene, isobutylene or ethyl vinyl ether,polyacrylic, polyitaconic and polymaleic acids, and sulfoacrylicoligomers of M.W. as low as 1,000, available as Uniroyal ND-2.

Suitable generally are polymerized olefinically or ethylenicallyunsaturated carboxylic acids containing an activated carbon-to-carbonolefinic double bond and at least one carboxyl group, that is, an acidcontaining an olefinic double bond which readily functions inpolymerization because of its presence in the monomer molecule either inthe alpha-beta position with respect to a carboxyl group or as part of aterminal methylene grouping. Illustrative of such acids are acrylic,methacrylic, ethacrylic, alpha-chloroacrylic, crotonic, beta-acryloxypropionic, sorbic, alpha-chlorsorbic, cinnamic, beta-styrylacrylic,muconic, itaconic, citraconic, mesaconic, glutaconic, aconitic,alpha-phenylacrylic, 2-benzyl acrylic, 2-cyclohexylacrylic, angelic,umbellic, fumaric, maleic acids and anhydrides. Other different olefinicmonomers copolymerizable with such carboxylic monomers includevinylacetate, vinyl chloride, dimethyl maleate and the like. Copolymerscontain sufficient carboxylic salt groups for water-solubility.

Also useful herein are carboxyvinyl polymers, disclosed as toothpastecomponents in U.S. Pat. No. 3,980,767 issued Sep. 14, 1976 to Choun etal, U.S. Pat. No. 3,935,306 issued Jan. 27, 1976 to Roberts et al, U.S.Pat. No. 3,919,409 issued Nov. 11, 1975 to Perla et al, U.S. Pat. No.3,911,904 issued Oct. 7, 1975 to Harrison, and U.S. Pat. No. 3,711,604issued Jan. 16, 1973 to Colodney et al. They are commercialciallyavailable for example under the trademarks Carbopol 934, 940 and 941 ofB. F. Goodrich, these products consisting essentially of a colloidallywater-soluble polymer of polyacrylic acid crosslinked with from about0.75% to about 2.0% of polyallyl sucrose or polyallyl pentaerythritol ascross-linking agent.

The synthetic anionic polymeric polycarboxylate component is mainly ahydrocarbon with optional halogen and O-containing substituents andlinkages as present in for example ester, ether and OH groups, and whenpresent is generally employed in the instant compositions in approximateweight amounts of 0.05 to 3%, preferably 0.05 to 2%, more preferably 0.1to 2%. Amounts in the upper portions of these ranges are typicallyemployed in dentifrice compositions typically containing a dentalabrasive and used in conjunction with brushing of the teeth, e.g. toothpastes (including creams), gels, powders and tablets. Amounts in excessof these ranges may be employed for thickening or gelling purposes.

As indicated above, these polymeric polycarboxylates have been found tobe effective inhibitors of alkaline phosphatase enzyme. Since thisenzyme has little activity (for hydrolyzing pyrophosphate) at about pH7.0 or below, the polymeric polycarboxylate component may, if desired,be omitted from oral preparations formulated to operate at such pH of7.0 or below. Such omission however obviously reduces the versatilityand effectiveness of the present oral compositions over the broad pHrange of about 4.5 to about 10.

The sources of fluoride ions, or fluoride-providing compounds, requiredaccording to this invention as an essential acid phosphatase andpyrophosphatase enzyme inhibitor component are well known in the art asanti-caries agents and also act as such agents in the practice of thisinvention. These compounds may be slightly soluble in water or may befully water-soluble. They are characterized by their ability to releasefluoride ions in water and by freedom from undesired reaction with othercompounds of the oral preparation. Among these materials are inorganicfluoride salts, such as soluble alkali metal, alkaline earth metalsalts, for example, sodium fluoride, potassium fluoride, ammoniumfluoride, calcium fluoride, a copper fluoride such as cuprous fluoride,zinc fluoride, barium fluoride, sodium fluorsilicate, ammoniumfluorosilicate, sodium fluorozirconate, sodium monofluorophosphate,aluminum mono- and di-fluorophosphate, and fluorinated sodium calciumpyrophosphate. Alkali metal and tin fluorides, such as sodium andstannous fluorides, sodium monofluorophosphate (MFP) and mixturesthereof, are preferred.

The amount of fluoride-providing compound is dependent to some extentupon the type of compound, its solubility, and the type of oralpreparation, but it must be a nontoxic amount, generally about 0.005 toabout 3.0% in the preparation. In a dentifrice preparation, e.g. dentalgel, toothpaste (including cream), toothpowder, or dental tablet, anamount of such compound which releases up to about 5,000 ppm of F ion byweight of the preparation is considered satisfactory. Any suitableminimum amount of such compound may be used, but it is preferable toemploy sufficient compound to release about 300 to 2,000 ppm, morepreferably about 800 to about 1,500 ppm of fluoride ion. Typically, inthe cases of alkali metal fluorides and stannous fluoride, thiscomponent is present in an amount up to about 2% by weight, based on theweight of the preparation, and preferably in the range of about 0.05% to1%. In the case of sodium monofluorophosphate, the compound may bepresent in an amount of about 0.1-3%, more typically about 0.76%.

In dentifrice preparations such as lozenges and chewing gum, thefluoride-providing compound is typically present in an amount sufficientto release up to about 500 ppm, preferably about 25 to 300 ppm by weightof fluoride ion. Generally about 0.005 to about 1.0 wt. % of suchcompound is present.

The dentifrice compositions of this invention achieve the desiredanticalculus effect by mixing therein about 4.3% to about 7% oftetrapotassium pyrophosphate alone or with up to 2.7% of tetrasodiumpyrophosphate. Preferred ratios of the tetrapotassium:tetrasodium saltsrange from about 4.3:2.7 to about 6:1, especially a ratio of 4.5:1.5.Contrary to the disclosure in the aforementioned Parran et al patent, itis highly significant that the compositions of this invention havehighly acceptable anticalculus and improved cosmetic properties whileincluding more than 4.0% of the tetrapotassium pyrophosphate and withoutinclusion of any dialkali metal pyrophosphate, although small amountsthereof, such as about 0.1% to about 0.4% or about 1.0% may be soincluded if desired.

The pH of the dentifrice preparations of this invention is generally inthe range of from about 4.5 to about 10 and typically from about 5.5 to9. The pH is preferably in the range of from about 6 to about 8.0. It isnoteworthy that the compositions of the invention may be applied orallyat said pH ranges without substantially decalcifying or otherwisedamaging dental enamel. The pH can be controlled with acid (e.g. citricacid or benzoic acid) or base (e.g. sodium hydroxide) or buffered (aswith sodium citrate, benzoate, carbonate, or bicarbonate, disodiumhydrogen phosphate, sodium dihydrogen phosphate, etc.).

In certain desirable forms of this invention, the dentifrice compositionmay be substantially solid or pasty in character, such as toothpowder, adental tablet, a toothpaste (cream), or a dental gel. The vehicle ofsuch solid or pasty dentifrice preparations typically contains an orallyor dentally acceptable polishing material for use in conjunction with abrushing of the teeth. Examples of such polishing materials arewater-insoluble sodium metaphosphate, potassium metaphosphate,tricalcium phosphate, dihydrated calcium phosphate, anhydrous dicalciumphosphate, calcium pyrophosphate, magnesium orthophosphate, trimagnesiumphosphate, calcium carbonate, aluminum silicate, zirconium silicate,silica, bentonite, and mixtures thereof. Other suitable polishingmaterials include the particulate thermosetting resins described in U.S.Pat. No. 4,070,510 of Dec. 15, 1962 such as melamine-, phenolic-, andurea-formaldehydes, and cross-linked polyepoxides and polyesters.Preferred polishing materials include crystalline silica having particlesizes of up to about 5 microns, a mean particle size of up to about 1.1microns, and a surface area of up to about 50,000 cm.^(2/) gm., silicagel or colloidal silica, and complex amorphous alkali metalalumino-silicate.

When visually clear gels are desired, a polishing agent of colloidalsilica, such as those sold under the trademark SYLOID as Syloid 72 andSyloid 74 or under the trademark SANTOCEL as Santocel 100 and alkalimetal aluminosilicate complexes are particularly useful, since they haverefractive indices close to the refractive indices of gellingagent-liquid (including water and/or humectant) systems commonly used indentifrices.

Many of the so-called "water-insoluble" polishing materials are anionicin character and also include small amounts of soluble material. Thus,insoluble sodium metaphosphate may be formed in any suitable manner asillustrated by Thorpe's Dictionary of Applied Chemistry. Volume 9, 4thEdition, pp. 510-511. The forms of insoluble sodium metaphosphate knownas Madrell's salt and Kurrol's salt are further examples of suitablematerials. These metaphosphate salts exhibit only a minute solubility inwater, and therefore are commonly referred to as insolublemetaphosphates (IMP). There is present therein a minor amount of solublephosphate material as impurities, usually a few percent such as up to 4%by weight. The amount of soluble phosphate material, which is believedto include a soluble sodium trimetaphosphate in the case of insolublemetaphosphate, may be reduced or eliminated by washing with water ifdesired. The insoluble alkali metal metaphosphate is typically employedin powder form of a particle size such that no more than about 1% of thematerial is larger than about 37 microns.

The polishing material is generally present in the solid or pastycompositions in weight concentrations of about 10% to about 99%.Preferably, it is present in amounts ranging from about 10% to about 75%in toothpaste or gel and from about 70% to about 99% in toothpowder ortablet.

In a toothpaste, the liquid vehicle may comprise water and humectanttypically in an amount ranging from about 10% to about 90% by weight ofthe preparation. Glycerine, propylene glycol, sorbitol, polypropyleneglycol and/or polyethylene glycol (e.g. 400-600) exemplify suitablehumectants/carriers. Also advantageous are liquid mixtures of water,glycerine and sorbitol. In clear gels where the refractive index is animportant consideration, about 3-30 wt. % of water, 0 to about 80 wt. %of glycerine, and about 20-80 wt. % of sorbitol is preferably employed.

Toothpastes (creams) and gels typically contain a natural or syntheticthickener or gelling agent in proportions of about 0.1 to about 10,preferably about 0.5 to about 5, wt. %. A suitable thickener issynthetic hectorite, a synthetic colloidal magnesium alkali metalsilicate complex clay available for example as Laponite (e.g. CP, SP2002, D) marketed by Laporte Industries Limited. Laponite D analysisshows, approximately by weight, 58.00% SiO₂, 25.40% MgO, 3.05% Na₂ O,0.98% Li₂ O, and some water and trace metals. Its true specific gravityis 2.53 and it has an apparent bulk density (g./ml. at 8% moisture) of1.0.

Other suitable thickeners include Irish moss, gum tragacanth, starch,polyvinylpyrrolidone, hydroxyethylpropylcellulose, hydroxybutyl methylcellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose (e.g.available as Natrosol), sodium carboxymethyl cellulose, and colloidalsilica such as finely ground Syloid (e.g. 244).

It will be understood that, as is conventional, the oral preparationsare to be sold or otherwise distributed in suitable labelled packages.Thus, a toothpaste, cream or gel will usually be in a collapsible tube,typically aluminum, lined lead or plastic, or other squeeze, pump orpressurized dispenser for metering out the contents, having a labeldescribing it, in substance, as a toothpaste, gel or dental cream.

Organic surface-active agent are used in the compositions of the presentinvention to achieve increased prophylactic action, assist in achievingthorough and complete dispersion of the anticalculus agent throughoutthe oral cavity, and render the instant compositions more cosmeticallyacceptable. The organic surface-active material is preferably anionic,nonionic or ampholytic in nature, and it is preferred to employ as thesurface-active agent a detersive material which imparts to thecomposition detersive and foaming properties. Suitable examples ofanionic surfactants are water-soluble salts of higher fatty acidmonoglyceride monosulfates, such as the sodium salt of the monosulfatedmonoglyceride of hydrogenated coconut oil fatty acids, higher alkylsulfates such as sodium lauryl sulfate, alkyl aryl sulfonates such assodium dodecyl benzene sulfonate, higher alkyl sulfoacetates, higherfatty acid esters of 1,2 dihydroxy propane sulfonate, and thesubstantially saturated higher aliphatic acyl amides of lower aliphaticamino carboxylic acid compounds, such as those having 12 to 16 carbonsin the fatty acid, alkyl or acyl radicals, and the like. Examples of thelast mentioned amides are N-lauroyl sarcosine, and the sodium,potassium, and ethanolamine salts of N-lauroyl, N-myristoyl, orN-palmitoyl sarcosine which should be substantially free from soap orsimilar higher fatty acid material. The use of these sarcosinatecompounds in the oral compositions of the present invention isparticularly advantageous since these materials exhibit a prolonged andmarked effect in the inhibition of acid formation in the oral cavity dueto carbohydrate breakdown in addition to exerting some reduction in thesolubility of tooth enamel in acid solutions.

Examples of water-soluble nonionic surfactants are condensation productsof ethylene oxide with various reactive hydrogen-containing compoundsreactive therewith having long hydrophobic chains (e.g. aliphatic chainsof about 12 to 20 carbon atoms), which condensation products("ethoxamers") contain hydrophilic polyoxyethylene moieties, such ascondensation products of poly (ethylene oxide) with fatty acids, fattyalcohols, fatty amides, polyhydric alcohols (e.g. sorbitan monostearate)and polypropyleneoxide (e.g. pluronic materials).

Various other materials may be incorporated in the oral preparations ofthis invention such as whitening agents, preservatives, silicones,chlorophyll compounds, other anticalculus agents, and/or ammoniatedmaterial such as urea, diammonium phosphate, and mixtures thereof. Theseadjuvants, where present, are incorporated in the preparations inamounts which do not substantially adversely affect the properties andcharacteristics desired. Significant amounts of zinc, magnesium andother metal salts and materials, generally soluble, which would complexwith the active components of the instant invention are to be avoided.

Any suitable flavoring or sweetening material may also be employed.Examples of suitable flavoring constituents are flavoring oils, e.g. oilof spearmint, peppermint, wintergreen, sassafras, clove, sage,eucalyptus, marjoram, cinnamon, lemon, and orange, and methylsalicylate. Suitable sweetening agents include sucrose, lactose,maltose, dextrose, levulose, sorbitol, xylitol, d-tryptophan,dihydrochalcones, sodium cyclamate, perillartine, APM (aspartyl phenylalanine, methyl ester), saccharine and the like. Suitably, flavor andsweetening agents may together comprise from about 0.1% to 5% or more ofthe preparation.

In the preferred practice of this invention an oral compositionaccording to this invention such as dentifrice containing the describedpyrophosphate and enzyme inhibitor in an amount effective to inhibitcalculus on dental surfaces is preferably applied as by brushingregularly to dental enamel, such as every second or third day orpreferably from 1 to 3 times daily, at a pH of about 4.5 to about 10,generally about 5.5 to about 9, preferably about 6 to 8, for at least 2weeks up to 8 weeks or more up to lifetime. The dentifrice is typicallyremoved by rinsing with water after each application.

The compositions of this invention can be incorporated in lozenges, orin chewing gum or other products, e.g. by stirring into a warm gum baseor coating the outer surface of a gum base, illustrative of which may bementioned jelutone, rubber latex, vinylite resins, etc., desirably withconventional plasticizers or softeners, sugar or other sweeteners orcarbohydrates such as glucose, sorbitol and the like.

The vehicle or carrier in a tablet or lozenge is a non-cariogenic solidwater soluble polyhydric alcohol (polyol) such as mannitol, xylitol,sorbitol, maltitol, a hydrogenated starch hydrolysate, Lycasin,hydrogenated glucose, hydrogenated disaccharides, and hydrogenatedpolysaccharides, in an amount of about 90-98% by weight of the totalcomposition. Solid salts such as sodium bicarbonate, sodium chloride,potassium bicarbonate or potassium chloride may totally or partiallyreplace the polyol carrier.

Tableting lubricants, in minor amounts of about 0.1 to 5% by weight, maybe incorporated into the tablet or lozenge formulation to facilitate thepreparation of both the tablets and lozenges. Suitable lubricantsinclude vegetable oils such as coconut oil, magnesium stearate, aluminumstearate, talc, starch and carbowax.

Lozenge formulations contain about 2% gum as barrier agent to provide ashiny surface as opposed to a tablet which has a smooth finish. Suitablenon-cariogenic gums include Kappa carrageenan, carboxymethyl cellulose,hydroxyethyl cellulose, Gantrez, and the like.

The lozenge or tablet may optionally be coated with a coating materialsuch as waxes, shellac, carboxymethyl cellulose, polyethylene/maleicanhydride copolymer or Kappa-carrageenan to further increase the time ittakes the tablet or lozenge to dissolve in the mouth. The uncoatedtablet or lozenge is slow dissolving, providing a sustained release rateof active ingredients of about 3 to 5 minutes. Accordingly, the soliddose tablet and lozenge composition of this invention affords arelatively longer time period of contact of the teeth in the oral cavitywith the active ingredients.

The following examples are further illustrative of the nature of thepresent invention, but it is understood that the invention is notlimited thereto. All amounts and proportions referred to herein and inthe appended claims are by weight and temperatures are in degrees C.unless otherwise indicated.

EXAMPLE A Effect of Salivary Enzymes on Inhibition of HAP Formation byTSPP

The in vitro formation of HAP is measured titrimetrically via a pH statprocedure. Stock solutions of 0.1M CaCl₂ and 0.1M NaH₂ PO₄ are preparedfresh in carbonate-free deionized distilled water. To 23 ml CO₂ -freedeionized distilled 1.0 ml. of the stock phosphate solution and 1.0 ml.of an aqueous solution of 1×10⁴ of the anticalculus agent being testedare added followed by 1.0 ml. of the stock calcium chloride solutionwhich initiates the reaction. The reaction is conducted at pH 7.4 undera nitrogen atmosphere. Consumption of 0.1N NaOH is recordedautomatically from which the time required for crystal formation isdetermined. Table A shows the results of this procedure.

                  TABLE A                                                         ______________________________________                                               Time of Crystal Growth Inhibition (Hrs.)                               Anticalculus              Pyro-     Alk.                                      Agent    Water    Saliva  Phosphatase                                                                             Phosphatase                               ______________________________________                                        TSPP*    0.8      0.4     0.3       0.0                                       ______________________________________                                         *Tetrasodium pyrophosphate                                               

Table A shows that in water TSPP significantly delays HAP formation.However, the effectiveness of this agent is drastically reduced whenincubated with saliva as evidenced by the shorter delay time. Thisreduction in efficacy is due to the enzymatic hydrolysis of P-O-P bonds.Incubation of this agent with pyrophosphatase and alkaline phosphatasedrastically reduces the delay period and indicates the susceptibility ofthe P-O-P bond to hydrolysis by phosphatases. Substantially the sameresults are obtained using tetrapotassium pyrophosphate (TKPP) insteadof TSPP, both having the same effective P-O-P bond-containingpyrophsophate ion.

EXAMPLE B Stabilization of TSPP to Enzymatic Hydrolysis in Presence ofInhibitors

Enzymatic hydrolysis is conducted in 100 millimolar morpholinopropanesulfonic acid - NaOH buffer solution (pH 7.0) containing 1.3 mg./ml ofTSPP. Inhibitors of this invention are added (except to the control) toa final concentration of 1,000 ppm fluoride ion (from NaF) and 0.5% ofthe sodium salt of hydrolyzed methoxyethylene-maleic anhydride (1:1)copolymer, M.W. 70,000 (Gantrez S-97 Pharmaceutical Grade). Equalactivities of acid phosphatase, alkaline phosphatase, and inorganicpyrophosphatase are then added to yield a total phosphatase activity of0.3 units/ml. Samples of the test solution are taken and totalorthophosphate available in each sample measured after 3 hourshydrolysis in 4N HCl at 100° C. The reaction mixture is incubated at 37°C. with shaking and aliquots taken at appropriate times through at least90 minutes for orthophosphate determination. Table 1 shows the resultsexpressed as percent orthophosphate released due to hydrolysis of thepyrophosphate.

                  TABLE B                                                         ______________________________________                                                 Percent Orthophosphate                                                        Released in 90 min.                                                  Anticalculus         With     Percent Relative                                Agent    Control     Inhibitors                                                                             Protection                                      ______________________________________                                        TSPP     98          58       41                                              ______________________________________                                    

Table B shows that after 90 min. incubation in the presence of enzyme98% of the available orthophosphate is released from the TSPP in theabsence of the inhibitors. With inhibitors, hydrolysis of P-O-P bonds inpyrophosphate (TSPP) is reduced by 41%. It should be noted that theenzyme activities used in this study are at least 2-3 fold greater thanthose normally found in saliva. These data indicate that the inhibitorsof this invention significantly reduce enzymatic hydrolysis of TSPP.Substantially the same results are obtained when equivalent amounts ofTKPP is substituted for the TSPP.

The following dental gel formulations are representative of theinvention. Example 1 is a white opacified gel, Example 2 is a bluetransparent gel.

    ______________________________________                                                         Parts by Weight                                                               Example 1                                                                              Example 2                                           ______________________________________                                        Part 1                                                                        TSPP               1.500      1.500                                           TKPP               4.500      4.500                                           Sorbitol (70% Aqueous Solution)                                                                  22.507     22.500                                          Part 2                                                                        Polyethylene Glycol 600                                                                          5.000      5.000                                           Glycerine          10.750 750 15.000                                          IOTA Carrageenan Gum                                                                             0.500      0.450                                           Sodium Fluoride    0.243      0.243                                           Sodium Saccharin   0.300      0 300                                           Gantrez S-97       1.000      1.000                                           Titanium Dioxide   0.500      --                                              Deionized Water    31.000     26.607                                          FD & C Blue #1 (1% Solution)                                                                     --         0.200                                           Part 3                                                                        ZEO 49B (SiO.sub.2)                                                                              17.000     16.000                                          SYLOID 244 (Synthetic Silica)                                                                    3.000      4.500                                           Part 4                                                                        Sodium Lauryl Sulfate Powder                                                                     1.200      1.200                                           Flavor             1.000      1.000                                           ______________________________________                                    

The above formulations are prepared as follows: The components of Part 1are mixed to solution form. Separately, the components of Part 2, exceptthe water, are mixed to form a dispersion in the polyethyleneglycol/glycerin humectant, and the water then mixed in. Parts 1 and 2are then combined, followed by consecutive addition, with suitablemixing, of Parts 3 and 4. These and the following formulations aredesigned to retain the anti-caries effect of the fluoride componentsubstantially uneffected by the other components, and to produce nosignificant tooth erosion effects.

EXAMPLE 3

Employing the same procedure as in Example 1 and 2, the followingtoothpaste formulation is prepared in accordance with this invention.

    ______________________________________                                        Ingredient            Parts by Weight                                         ______________________________________                                        Deionized water       37.578                                                  Glycerin              25.000                                                  Zeo 49B (Silicon Dioxide)                                                                           21.500                                                  TKPP                  4.500                                                   TSPP                  1.500                                                   Syloid 244 (synthetic silica)                                                                       3.000                                                   Sodium Lauryl Sulfate 1.200                                                   Flavor                1.000                                                   Gantrez S-97 Pharmaceutical Grade                                                                   1.000                                                   Sodium Hydroxide (50% Solution)                                                                     1.000                                                   Xanthan Gum           1.000                                                   Sodium Benzoate       0.500                                                   Titanium Dioxide      0.500                                                   Sodium Saccharin      0.300                                                   Sodium Fluoride       0.242                                                   ______________________________________                                    

Examples 4 and 5 represent lozenge formulations according to theinvention.

    ______________________________________                                        Example 4                                                                     Lozenge Formulations                                                                       Parts by Weight                                                  ______________________________________                                        Sugar          75-98                                                          Cornsyrup       1-20                                                          Flavor Oil     0.1-1.0                                                        Tablet lubricant                                                                             0.1-5                                                          TKPP:TSPP-3:1  3.5-8                                                          Gantrez S-97   0.05-3                                                         NaF            0.01-0.05                                                      Water          0.01-0.2                                                       ______________________________________                                    

    ______________________________________                                        Example 5                                                                     Lozenge                                                                                         Weight                                                                        Percent                                                     ______________________________________                                        Sodium saccharin    0.15                                                      Flavor              0.25                                                      Color               0.01                                                      Emulsifying Agent*  1.00                                                      NaF                 0.05                                                      Gantrez S-97        0.30                                                      TKPP:TSPP-3:1       6.50                                                      Sorbitol            QS to 100                                                 ______________________________________                                         *PEG (40) Sorbitan Diisostearate                                         

    ______________________________________                                        Example 6                                                                     Chewing Gum                                                                                       Parts                                                     ______________________________________                                        Gum base              10    to 50                                             Binder                3     to 10                                             Filler                5     to 80                                             (sorbitol, mannitol or                                                        combination thereof)                                                          Artificial sweetener  0.1   to 5                                              TKPP:TSPP-3:1         3.5   to 8                                              Gantrez S-97          0.1   to 1.0                                            NaF                   0.1   to 0.05                                           Flavor                0.1   to 5                                              ______________________________________                                    

All the above formulations have been designed to provide improvednon-gritty and other cosmetic properties and to exert improvedanticalculus effects in vivo.

This invention has been described with respect to certain preferredembodiments and it will be understood that modifications and variationsthereof obvious to those skilled in the art are to be included withinthe purview of this application and the scope of the appended claims.

We claim:
 1. In an oral composition containing an orally acceptableaqueous vehicle and, in approximate weight amounts and proportions,A. amixture of tetrasodium pyrophosphate and tetrapotassium pyrophosphate aseffective anticalculus agent, and B. an amount of a fluoride ion sourcesufficient to supply 25 ppm to 5,000 ppm of fluoride ions, theimprovement in which the tetrapotassium pyrophosphate is a predominantportion of said mixture, which portion is sufficient to inhibit theoccurrence of solid gritty particles of tetrasodium pyrophosphate in thecomposition.
 2. The composition of claim 1 further containing an amountup to 0.4% of dialkali metal pyrophosphate effective to assist inachieving the desired anticalculus and cosmetic properties.
 3. Thecomposition of claim 1 further containing an amount up to 1% of dialkalimetal pyrophosphate effective to assist in achieving the desiredanticalculus and cosmetic properties.
 4. The composition of claim 1further containing an orally acceptable silica abrasive.
 5. Thecomposition of claim 4 in which the fluoride ion source comprises sodiumfluoride.
 6. The composition of claim 4 in which the fluoride ion sourcecomprises sodium monofluorophosphate.
 7. The composition of claim 1 inwhich the fluoride ion source comprises sodium fluoride.
 8. Thecomposition of claim 1 in which the fluoride ion source comprises sodiummonofluorophosphate.
 9. A method of inhibiting dental calculuscomprising applying to dental surfaces an effective inhibiting amount ofa composition as defined in claim
 1. 10. A method of inhibiting dentalcalculus comprising applying to dental surfaces an effective inhibitingamount of a composition as defined in claim
 2. 11. A method ofinhibiting dental calculus comprising applying to dental surfaces aneffective inhibiting amount of a composition as defined in claim
 3. 12.A method of inhibiting dental calculus comprising applying to dentalsurfaces an effective inhibiting amount of a composition as defined inclaim
 4. 13. A method of inhibiting dental calculus comprising applyingto dental surfaces an effective inhibiting amount of a composition asdefined in claim
 5. 14. A method of inhibiting dental calculuscomprising applying to dental surfaces an effective inhibiting amount ofa composition as defined in claim
 6. 15. A method of inhibiting dentalcalculus comprising applying to dental surfaces an effective inhibitingamount of a composition as defined in claim
 7. 16. A method ofinhibiting dental calculus comprising applying to dental surfaces aneffective inhibiting amount of a composition as defined in claim 8.